After 2 years and over 65,000 episodes of anime, I find I have very specific tastes - hate yaoi shows (like DRR, KHR, even Gintama to an extent), loli shows (K-ON and the like), moe shows (Haruhi, K-ON, the show where there's this loli girl detective who rolls on the floor - WTF is that?, plenty more), cliché shows (Naruto - screw the 10 billion flashbacks and stupid fillers, Bleach - villain = strawberry levels up = villain gone = another new villain = strawberry levels up = villain gone = new villain... repeat 200 billion times, every single school-based anime, though there are exceptions like Lucky Star/Hotd/Fuujin Monogatari, every single mecha anime, though there are exceptions like TTGL), hyperactive girl shows (like Miyazaki and his loli fetish for hyperactive little girl heroines that always run at 572 mph with eyes as wide as truck headlamps), bossy female shows (too many to list), cutesy shows (like that dango kazoku show)... basically any show that offers sub-par entertainment.
As the Jump editor tells Oonishi in Gintama (which would've been an amazing show if it weren't for all the yaoi refs), "Don't use sex and cliché to cover up your unimaginative stories".
Hentai is porn and has no place in my list. Not that I'm not into porn, I neither like it nor hate it; just that I believe there's a right time and place for everything and also 'cause I don't consider porn to be 'entertainment'. If one doesn't pee for 17 hours and then lets loose, the relief one feels is 'highly satisfying' but it is not 'entertainment'. Porn is the same deal. It's relief, not entertainment.
Innovative, imaginative (not to be confused with the 'fantasy' genre although I absolutely love fantasy shows like Inuyasha, Spice & Wolf) and funny stories preferably topped with great sound and action are my favorite - Initial D, GitS, Koi Kaze, GTO, Hajime no Ippo, Honey & Clover, Gintama (all the yaoi refs are a -major- turnoff though), Spriggan... basically shows rated 8 and above in my anime list.
But I like something even more - 'slice of life' shows. Maison Ikkoku, Hōhokekyo Tonari no Yamada-kun, Genshiken, Mushishi, Gintama (the yaoi refs suck big time though) and a bunch more great shows.
tl;dr - After watching a shit-ton of anime, I finally discovered I'm a purist who gets bored real fast and has low tolerance for BS.